BIOS (Basic Input Output System) is adapted to handle all input and output functions when a computer is turned on. There is a small difference between two BOSS produced by any two manufacturers. However, in general, any type of BIOS is adapted to perform the following steps after a computer is turned on.
(1) First, the internal power supply of the computer will start only after a stable power is outputted from an external power source. Otherwise, the computer may be damaged. Next, a chips et of the mother board of the computer issues a reset signal to a processor (e.g., CPU (central processing unit)) so that the processor may reset the computer prior to entering a state of waiting for an instruction.
(2) After receiving the reset signal, the processor waits the input of instruction. The processor will process an input instruction. At this time, there is no data in the processor. Previously performed actions are interrupted and data is initialized. Based on the scheme of processor, the processor is required to access a next instruction (e.g., program for initializing the computer) to be executed from BIOS ROM. Typically, the location of the program is fixed (e.g., addressed at FFFF0h of the end of memory). It is advantageous for avoiding the processor from being redesigned when BIOS is enhanced for matching added functions. Typically, the instruction in the address is a simple jump instruction. That is, the jump instruction is adapted to command the processor to jump to another location of the memory where is the beginning address of the computer initialization.
(3) BIOS is adapted to perform a self test to check whether there is fatal error when the computer is turned on. If there is such error (e.g., one that prevents a normal start from occurring) a POST (power on self test) performed by BIOS sounds a warning. An experienced computer user or engineer typically knows the meaning of the sound. No data is shown on the computer monitor at this time. Thus, there is no way of detecting the error if the above action (i.e., POST) is not taken.
(4) Next, BIOS attempts to find a graphics card of the computer and then locates BIOS location of the graphics card if it is found. BIOS of the graphics card is adapted to enable BIOS of the computer to call and take advantage of the graphics card. Procedures of BIOS are stored at address C000h of memory. Initialization of the graphics card can be finished after performing BIOS. Typically, information about hardware including the graphics card is shown on the monitor at this time. For example, hardware information is shown on the monitor after performing the main BIOS before the appearance of energy star icon.
(5) The main BIOS then searches BIOS of any other equipment of the computer and executes the same if found. For example, BIOS of RIDE/DATA hard disk drive can be found at address C8000h. Moreover, the main BIOS will execute BIOS of any found equipment.
(6) A start screen (e.g., one containing an energy star icon) is shown after BIOS activating the graphics card.
(7) BIOS then performs other test actions including memory test and a result thereof will be shown on the monitor. Reasons of any error will be shown on the monitor if such error occurs during this test period. This is because the determination of whether the graphics card is correct or not has been done. In such a manner, any occurred error is apparent to computer user. Thus, the user is able to correct the error.
(8) After performing the test actions in step (7), BIOS knows the current status of any equipment of the computer and thus is able to establish a system table thereafter. Currently, BIOS is very good in automatically detecting system configuration and settings. For example, memory access rate can be automatically detected and set by BIOS. Moreover, BIOS is able to automatically detect hard disk configuration and access mode. Latest BIOS is also able to detect any externally connected hard disk drive. Typically, such equipment is connected to COM or LET port of computer.
(9) For BIOS supporting PAP (Plug and Play), BIOS then has to detect any PAP devices of the computer. Also, description of any found PAP device will be shown on the monitor. The computer is thus able to set the configuration of the PAP device and use the same thereafter (i.e., the PAP device is supported by the computer).
(10) The computer monitor is then scrolled in which BIOS is adapted to show the current status of the computer on the monitor such that not only system configuration is shown but also any installation problem is apparent by referring to the system configuration.
(11) After initializing hardware, BIOS then has to find information from the booting for loading into SO (operating system) such that SO is able to process a portion of tasks. Prior to reading data, BIOS has to know where data is located. Typically, a user may activate a floppy disk, an RIDE or SCSI hard disk, or a CD-ROM drive to boot a computer. Also, an order of searching the above devices (i.e., drives) is preset in BIOS. Next, BIOS searches the above devices by following the order prior to reading boot data from the first found device (i.e., system disk).
(12) After finding the booted device, BIOS then reads data therefrom prior to loading into SO. Typically, after turning on the computer (i.e., activating hard disk drive), BIOS finds a location of cluster 0, head 0, and sector 1 from the master hard disk for accessing boot data. The location is also the first sector of the hard disk. Similarly, BIOS will find the same location from a floppy disk for accessing boot data if the floppy disk is the default system disk.
(13) Next, BIOS searches the above drives by following the order prior to reading boot data from the first found drive. The read data is then loaded to activate SO. BIOS then writes program codes stored at the location into memory and executes the same. As a result, procedures for activating SO are performed.
(14) An error message indicating no system disk is shown on the monitor if BIOS does not find any system disk after fully searching the above drives. Typically, BIOS will ask a user to insert a system diskette into a floppy disk drive if no hard disk is available or no diskette is inserted into the floppy disk drive for turning on the computer. BIOS will show a message such as “Disk boot failure, insert . . . ” on the monitor if there is no boot data available from hard or floppy disk drive. A user may insert a system diskette into the floppy disk drive for starting the computer. Another reason for the boot failure is that no active partition of the hard disk drive is programmed previously.
A computer can start normally if none of the following hardware and software components including CPU, memory, CMOS, setting, and battery is found bad after performing BIOS POST However, an error message is shown on the monitor if there is at least one malfunctioned component. Also, POST is interrupted temporarily. A user may turn off the computer to eliminate the source of trouble and turn on the computer thereafter. However, it is not easy for a user to eliminate the source of trouble since only a short message (e.g., CPU error) is shown. Thus, it is desirable among the art to provide a novel method of providing a real time solution to an error occurred when a computer is turned on in order to overcome the above problems of prior art.